PARENT SESSION
Contributed Oral Session 150: Evolutionary Ecology: Landscapes and Habitat
Friday, August 12, 8:00 AM - 11:30 AM, Meeting Room 513 A, Level 5, Palais des congrès de Montréal
Mechanisms of species extinction in dynamic landscapes.
Pillai, Pradeep*,1, Guichard, Frédéric 1, 1 McGill University, Montreal, Québec, Canada
ABSTRACT- Recent theoretical and empirical efforts reveal the difficulty of testing the relative importance of trade-off vs. neutral processes in shaping macroecological patterns. While most studies of neutral theory posit homogeneous habitats, trade-off communities have been used to predict the response of communities to habitat fragmentation. The integration of habitat fragmentation in the current debate on community organisation is thus required. The standard models for studying the spatial effects of habitat fragmentation on species communities assume static habitat cover and thus ignore habitat dynamics. We report results from a spatially-explicit community model controlling for (1) community structure (neutral vs. trade-off) and (2) for the spatial structure (local vs. well-mixed) of habitat and community dynamics. The model is used to elucidate the mechanisms of species extinction in dynamic landscapes. Our research was able to show that the response of species richness to habitat loss is highly dependent on either local processes of habitat dynamics or on species assembly rules. We more precisely show that when landscape creation and destruction processes are local, both neutral and trade-off structured communities show a similar and counterintuitive (positive) response to habitat fragmentation. In landscapes with well-mixed dynamics, the presence of life-history trade-offs were shown to be necessary for the community to be affected by habitat fragmentation, with neutral communities showing no discernable response to habitat availability. We were further able to quantify the relative roles of temporal dynamics (habitat patch turnover) and local spatial processes in relating species and habitat loss. These results suggest a possible approach to testing neutrality of communities colonizing dynamic landscapes.
Key words: community structure, neutral theory, extinction, habitat fragmentation